Fluid pressure tool



April 26,.1-93 2. G. M. NELL 1,855,723

FLUID PRESSURE TOOL Filed April 6. 1929 INVENTOR. Gusfuve M /|/e// A TTORNE Y.

Patented Apr. 26, 1932 UNITED STATES rAT-EN-r OFFICE.

GUSTAVE 1vr. NELL, 0E DETROIT, MICHIGAN, AssrcnoR TO CHICAGO PNEUMATIC TOOL COMPANY, OF NEW YORK, 1v. Y., A ooREot A'rIoN OF NEW JERSEY FLUID PRESSURE TooL Application filed April 6, 1929. Serial No. 353,208.

This invention relates to percussive tools of the fluid pressure type. More particularly it concerns the automatic control anddistribution of the motive fluid to the percussive. motor and the valve mechanism and porting,

' form movable walls for chambers 16 and 17 respectively, whichare continuously supplied with motive fluid in limited amount from the arrangement.

One ob ect of the lnvention is to provide a motor for tools of the described type having a valve structure which is simple and compact. Another object is to make the fluid and shifting ports between the valve and piston chambers short and direct. Another object. is to make the valve quick acting in its rever- V sals and the entire tool economical in the use Fig. 1 is a longitudinal sectional view through a fluid pressure rock drill; and

Fig. 2 is a sectional view similar to Fig. 1

but showing the piston and valve in different positions.

In the preferred form of the invention shown in the accompanying drawings, the percussive tool comprises a cylinder 3pro= vided with a piston chamber within which reciprocates a hammer piston 4 having a.

fluted extension 4:00 guided by a bushing 5 in the forward end of the cylinder and having cooperating sliding engagement with the fluted portion of a chuck 6 mounted for ro tation in a front head 7 A hollow drill steel bore of hollow valve 9. The ends of the valve 1 control the admission of motive fluid from the inlet to end chambers 12 and 13', depending upon the position of the valve, which end chambers communicate with the opposite ends of the piston chamber by short and direct ports 12a and l3a respectively. Valve 9 has a-radially'extending flange 9a providing opposed shift areas 14 and 15. These areas" central bore of the valve by ports 9?) through municate directly with the piston chamber on'opposite sides of main exhaust 3a through ports 16a and 17a, respectively, under control of piston 4. Intermediate chambers 16 and 12 on one side of flange 9a, and intermediate I chambers 17, and 13 on the other side, are vent chambers 18 and 19 respectively, which are alternately placed in communication" with end chambers 12 and 13 by 90 on the valve.-

With the tool in operation, and the parts in the position shown in Fig. 1, motive fluid annular grooves entering inlet 10a passes into chamber 12 and through passage 12a to the rear end of a the piston chamber, driving piston 4 forwardly. T he forward'end of the'chamb'er is open :to exhaust through main exhaust port 3a, through an auxiliary exhaust formed by the projection of the flutes on piston4a into thepiston chamber thereby establishing communication withthehollow bore of the drill steel, and by the valve controlled vent comprising'port13a, chamber 13, valve grooves 90, and vent chamber19. Portx17a, being uncovered, vents the motive fluid continually passing to chamber17 but that passing to chamber 16 is effective against area 14 to hold the valve in its forward position since p ort 16a is sealed by the piston. Of the two other pairs of opposing areas on the valve, the areas formed by the ends of the valve are in balance since both are in communication with the motive fluid supply, but the sealing projection or flange between chambers 12 and 18 assists in holding the valve in the forward direction since the corresponding pro]ect1on at the other end of the valve is disposed in a chamber open to exhaust.

'As the piston'advances it first covers the main exhaust 3a and then port 17a, whereupon pressure builds up in chamber 17 against area 15 to balance area 14. Shortly thereafter piston 4 overruns main exhaust 3a as it delivers its blow upon drill steel 8. The consequent drop in pressure in the rear end oi the piston chamber,.which is now in communication with flange chamber 16 through the uncovering of port 16a, causes a drop, in vpressure. in. chamber 16, resulting in a prompt shifting ofthe valve'to the position shown in Fig. 2 'by'reason ofthe predominating pressure in chamberl? eflective-z against shift area 15. With motive fluid now passing through thesboreiof valve 9e-into end chamber 13 and thence through port 13a -into3the forwardend 0tthe 'piston chamber'to drive the "piston rearwardlygwent' chamber 19 is *closed oil from 'end chamber 13whilevent ichamber 18 is in'communicationwith' the opthe' valve thereby establishing an auxiliary exhaust for-therear endof thepiston chamber. The val-ve'is held in its rearward position -through 'the' pressure on shiftarea 15 *and upon the sealing projection or flange -between'end chamber 13 and vent chamber 3 19. Asthe piston movesrearwafdlyiti closes ina-inexhaust 3a and. shortly thereafter the flutes on" piston extension 4a proj ect' into the forwardpiston chamber l causing" aslight-preduction in' I the pressure as a portion ofthe I motive fluidpasses along the flutes and down the hollow bore ofthe drill steel jto 'blow the 'cutti ngs out of the hole. 5 This drop in pressure is not suflicient to cause any shifting-of the: valve" and maybe :omitted =ientirely, if

? hole cleaningaonl the rbacki'strokeais not de- 7 sired, by arranging i'the' flutes. so that they 'ixdo'nnote rojiect intothezpi'ston chamber mmtil pistonei4-has opened-3.101:iszabouhtoiopen, main wex'haust 3a; With? the: uncovermgxof maan L .exshanstfiaa there-is: as pressure :drop in flange chamber? 17, whereupon: ithef predominating pressure against zth'e topposingsshift, area i 14 1 the ivzvlve zquickly'toifiorward position,

i thusrcompleting the @eycle.

,oWhi-le the invention is herein"? disclosed in avwhat: lSp'IID'W -.consi"der.ed to be. ac preferred iorinnitiis ato-kbe understood a that 1the inven- 513 time not limitedtothe; specific details there not but .covers Eallzchangesgmodificat-ion's, and adaptations within? the: s'copeof; the appended reclaims:

ilael'anmns my magenta-on it V :1 pressure:toolzcomprising a:cylin-- .der: providing a p1sto11-- chamber having .an :ezchanstnport, aapiston vreclproca-ble 11'1 said a :chamber and; arrange d to: overrun said port, sa1d cyl1nden providing a valve'case. ad acent q sai'di piston chamber, a tubular valve movable 21in. "said @casein i trmed relation with: "said p1srton-gsaid case providing chambersat-each end of the valve witlr ports'opening; i'ntothe ends as saidipiston cha mberg the ends of said valve econtroliingthesupplyofi motive fluid to said positeend chamber 12 through groove in end chambers, the bore of said valve serving as a conduit for the motive fluid and the end areas ofsaid valve being in open communication with said conduit in all positions of said valve, and a radial flange on said valve-intermediate the ends'thereof providing opposing shiit areas,-sa1d case providmg chambers on either side of said flange having ports open ng into sald piston chamber on opposite sl'des of -sald mam exhaust port 'and und'er control 'of'said' piston, said valve havingrestrioted ports therethrough on opposit'e sides of said flange to supply motive fluidcontinuouslyin limited amount to said flange chambers, said case providing vent chamberson either side. of-sznd flange be- -tween-said flange chambers and said end chambers, and means establishinga comiectionbetive'en each of saidend: chambers and the adjacent vent 'chamber'when said valve is in position to shut off the motivefluid supply to the said endchamber.

2;A fluidpressure tool comprising a cylzin- :der providing a'piston'chamberhaving an exhaust port, a P1812011:TGGIPIiOCHblQVlIII said: chamber 'san'd. ELTlflsl'lgBditO overrun said;- port,

saiidcylinder providing ava lvercase adjacent said. piston chamber, aitubularr-valve movable 1n "said case 1n timed 'relationi'with said piston, said-case provldingichambers at each end posing shift areas, said case providing-chain;

bersion either side :of said flange having ports .open-ingiinto said piston chamber on opposite sides of said main-exhaust port and'runder control of saidpiston, said valve having re- .zstricted ports'theret'hrongh on opposite sides of: said flange toisupp'ly motive fluid continuously in limited amount to said flange'chambers','sa'1d case providing vent chambers on either sideofsaid flange between said flange "chamberssand said end cha-mbers, and: means establishing aconnection between-each of said end. chambers andthe adj acent vent chamber when'csaid valve zis'yin positi'on" to shutzofi the motive fluid supply tothesaid'end chamber including grooves in said valve defining-annular progections in spaced relations to the 'end areas of saidvalve, said'projections alternately forming; holding *areas for said valve when in position toseal oflt said end chambers from said vent chambers.

Signed by me at -D'etroit,-in the county of 'Wayne, and State of Michigan this 23 day of March, 1929.

GUSTAVE M. NELL. 

